In the pharmaceutical industry, machines are used for filling capsules with pharmaceutical products.
Once filled, the capsules are transferred to weighing apparatus comprising a number of pockets, each for receiving and retaining a respective capsule.
The weighing apparatus also comprises a weighing system, in turn comprising, for each pocket, a measuring device for determining the weight of the capsule and the pharmaceutical product inside it.
The weighing system also comprises a processing unit for calculating the weight of the pharmaceutical product alone as the difference between the value measured by the measuring device, and a nominal value representing the weight of an empty capsule.
Since the nominal empty capsule weight value memorized in the processing unit of the weighing system is a theoretical value, and the actual weight of each empty capsule actually varies within a range comprising the nominal value, known apparatuses of the above type for weighing pharmaceutical product capsules are relatively inaccurate.
Very often, the actual weight of the pharmaceutical product inside each capsule may even differ from the theoretical weight calculated by the weighing system on the basis of the nominal empty capsule weight value.